Time and Location: 1:00 PM, with Q&A to follow; in a 1st floor conference room at the American Center for Physics (www.acp.org), 1 Physics Ellipse, College Park, MD ­ off River Rd., between Kenilworth Ave. and Paint Branch Parkway.

Abstract: East Africa is the source of much information about the evolution of early human ancestors. A synthesis of East African environmental data suggests that significant events in human origins typically developed during lengthy eras of strong climate fluctuation. Analysis of Earth’s orbital dynamics offers a new model of alternating high and low climate variability over the past 5 million years. This high/low variability model shows that fluctuations between arid and moist climate were important in the evolution of key human adaptations. The origin of the major early human lineages, critical transitions in stone technology, and the main geographic milestones in human origins all appear to coincide with prolonged intervals of intense climate variability. Climate dynamics and resource uncertainty likely shaped the adaptive versatility of our species, expressed by the expansion of mobile technologies, symbolic behavior, social networks, and behavioral diversity. The first long climate sequence obtained by drilling in the East African Rift Valley, at the site of Olorgesailie, Kenya, will test these ideas about the significance of adaptability in the origin of our species.

Biography: Paleoanthropologist Dr. Rick Potts directs the Human Origins Program at the Smithsonian’s National Museum of Natural History, where he holds the Peter Buck Chair in Human Origins. After receiving his PhD in biological anthropology at Harvard University in 1982, he taught at Yale before joining the Smithsonian in 1985. Rick’s research investigates Earth’s environmental dynamics and the processes that have led to human evolutionary adaptations. His ideas about the significant effect of environmental instability on human evolution have stimulated wide attention and new studies in the Earth sciences, paleontology, and experimental and computational biology. Rick leads ongoing excavations in the East African Rift Valley at fossil and archeological sites in southern Kenya and on the shores of Lake Victoria. He is curator of the Smithsonian’s Hall of Human Origins, and wrote the companion book for the current exhibit ‘What Does It Mean To Be Human?’